Charging base



FIG. 1 is a top, rear, left side perspective view of a charging base;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top, front, left side perspective view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a top plan view thereof.

The dash-dot-dash broken lines define boundaries of the charging base and form no part of the claimed design. The evenly spaced broken lines in the figures represent portions of the charging base which form no part of the claimed design. 

CLAIM The ornamental design for a charging base, as shown and described. 